Sedimentology of the Melawi and Kentungau Basins, West Kalimantan, Indonesia Rachmat Heryanto Sutjipto University of Wollongong
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University of Wollongong Research Online University of Wollongong Thesis Collection University of Wollongong Thesis Collections 1991 Sedimentology of the Melawi and Kentungau Basins, West Kalimantan, Indonesia Rachmat Heryanto Sutjipto University of Wollongong Recommended Citation Sutjipto, Rachmat Heryanto, Sedimentology of the Melawi and Kentungau Basins, West Kalimantan, Indonesia, Doctor of Philosophy thesis, Department of Geology, University of Wollongong, 1991. http://ro.uow.edu.au/theses/1405 Research Online is the open access institutional repository for the University of Wollongong. For further information contact Manager Repository Services: [email protected]. SEDIMENTOLOGY OF THE MELAWI AND KETUNGAU BASINS, WEST KALIMANTAN, INDONESIA VOLUME ONE A thesis submitted in (partial) fulfilment of the requirements for the award of the degree of DOCTOR OF PHILOSOPHY from THE UNIVERSITY OF UNIVERSITY j WOLLONGONG WOLLONGONG I LIBRARY 3 by RACHMAT HERYANTO SUTJIPTO (Ir ITB Bandung, MSc Wollongong Uni.) Department of Geology 1991 TABLE OF CONTENTS VOLUME ONE ABSTRACT ACKNOWLEDGEMENTS CHAPTER ONE - INTRODUCTION 1 1.1 BACKGROUND OF STUDY 1 1.2 LOCATION 1 1.3 PHYSIOGRAPHY 2 1.3.1 Lake District Depression 3 1.3.2 Upper Kapuas Meander Belt 3 1.3.3 Ketungau Hills 3 1.3.4 Central Topographic High 4 1.3.5 Melawi and Ketungau Peneplains 4 1.3.6 Madi Highland 4 1.3.7 Schwaner Mountains 5 1.4 CLIMATE, VEGETATION AND POPULATION 5 1.5 PREVIOUS GEOLOGICAL WORK 6 1.6 GEOLOGICAL BACKGROUND 7 1.6.1 Regional Geology 7 1.6.2 Local Geology 9 1.7 AIM OF THE STUDY 10 CHAPTER TWO - REGIONAL GEOLOGY 11 2.1 REGIONAL GEOLOGY 11 2.2 MELAWI BASIN 16 2.2.1 - Ingar Formation 17 2.2.2 Suwang Group 18 2.2.2a Dangkan Sandstone 19 2.2.2b Silat Shale 20 2.2.3 Melawi Group 22 2.2.3a Sepauk Sandstone 22 2.2.3b Payak Formation 24 2.2.3c Tebidah Formation 25 2.2.4 Kapuas Group 26 2.2.4a Sekayam Sandstone 26 2.2.4b Alat Sandstone 27 KETUNGAU BASIN 28 2.3.1 Merakai Group 29 2.3.la Kantu Formation 29 2.3.1b Tutoop Sandstone 30 2.3.Ic Ketungau Formation 32 PALAEONTOLOGICAL AGE CONTROL 33 2.4.1 Melawi Basin 33 2.4.2 Ketungau Basin 37 STRUCTURAL GEOLOGY 39 2.5.1 Northwestern Kalimantan Domain 40 2.5.2 Schwaner Zone 40 2.5.3 Submarine Cretaceous Zone 41 2.5.4 Boyan Melange Zone 41 2.5.5 Melawi Basin 42 2.5.5a Pre-Silat Fold Belt 42 2.5.5b Silat Fold Belt 42 2.5.5c Post-Silat Fold Belt 43 2.5.6 Lubok Antu Melange Zone 43 2.5.7 Ketungau Basin 44 CHAPTER THREE - SEDIMENTATION 45 3.1 SEDIMENTARY STRUCTURES 45 3.1.1 Hydrodynamic conditions from 46 sedimentary structures 3.1.2 Melawi Basin 48 3.1.2a Ingar Formation 48 3.1.2b Dangkan Sandstone 52 3.1.2c Silat Shale 57 3.1.2d Sepauk Sandstone 63 3.1.2e Payak Formation 64 3.1.2f Tebidah Formation 66 3.1.2g Sekayam Sandstone 71 3.1.2h Alat Sandstone 72 3.1.3 Ketungau Basin 7 5 3.1.3a Kantu Formation 75 3.1.3b Tutoop Sandstone 78 3.1.3c Ketungau Formation 81 3.2 LITHOFACIES 83 3.2.1 Melawi Basin Sequence 83 3.2.2 Ketungau Basin Sequence 89 CHAPTER FOUR - PETROGRAPHY 93 4.1 PETROGRAPHIC METHODS 9 3 4.2 PETROGRAPHIC RESULTS 94 4.2.1 Petrological Components in the 95 Melawi and Ketungau Basins 4.2.1a Quartz 95 4.2.1b Feldspar 97 4.2.1c Rock Fragments 98 4.2.Id Micas 99 4.2.1e Heavy Minerals 100 4.2.If Other Accessory Components 100 4.2.If Matrix 101 4.2.lg Cement 101 4.2.2 Petrological characteristics 102 of each formation 4.2.2a Ingar Formation 102 4.2.2b Suwang Group 104 4.2.2c Melawi Group 107 4.2.2d Kapuas Group 110 4.2.2e Merakai Group 113 4.3 CLUSTER ANALYSIS 116 4.3.1 Q-mode Analysis 118 4.3.1a Suwang Group 118 4.3.lb Melawi Group 119 4.3.Ic Kapuas Group 120 4.3.Id Merakai Group 122 4.3.Ie Relationships between groups 123 and basins 4.3.2 R-mode cluster analysis 128 4.4 IMPLICATIONS AND DISCUSSION 131 4.4.1 Melawi Basin 132 4.4.2 Ketungau Basin 135 CHAPTER FIVE - DIAGENESIS 137 5.1 INTRODUCTION 137 5.2 METHODS 138 5.2.1 Petrography 138 5.2.2 Scanning Electron Microscopy 139 (SEM) 5.2.3 X-ray Diffraction (XRD) 140 5.3 DIAGENETIC PROCESSES 141 141 5.3.1 Compaction 143 5.3.2 Authigenic Minerals 144 5.3.2a Quartz 145 5.3.2b Clay Minerals 149 5.3.2c Pyrite 149 5.3.2d Laumontite 150 5.3.2e Sphene 150 5.3.2f Calcite 151 5.3.2g Feldspar 151 5.3.3 Secondary Porosity 1535,. 4 DISCUSSION 161CIIAPTE R SIX - ORGANIC PETROLOGY 1616,. 1 INTRODUCTION 1636.. 2 RESULTS 163 6.2.1 Vitrinite Reflectance 166 6.2.2 Maceral Type 166 6.2.2a Melawi Basin 170 6.2.2b Ketungau Basin 6.3 DEPOSITIONAL SETTING BASED ON 171 MACERAL TYPE 6.4 COAL AND HYDROCARBON POTENTIAL 172 6.4.1 Coal Potential 172 6.4.2 Hydrocarbon Potential 176 6.4.2a Source Rock 176 6.4.2b Maturation 177 f.,4.2c Reservoir 178 5.4.2d Seals 180 6,4.2e Structure 181 6,4.2f Possibility of Hydrocarbon 181 Trapping CHAPTER SEVEN - DEPOSITIONAL AND 183 POST-DEPOSITIONAL HISTORY AND TECTONIC SETTING OF THE MELAWI AND KETUNGAU BASINS 7.1 PALAEOCURRENT ANALYSIS 183 7.2 DEPOSITIONAL ENVIRONMENT 186 7.2.1 Melawi Basin Sequence 186 7.2.1a Ingar Formation 187 7.2.1b Dangkan Sandstone 189 7,2.1c Silat Shale 193 7.2.Id Sepauk Sandstone 197 7.2.1e Payak Formation 198 7-2.If Tebidah Formation 201 7,2-lg Sekayam Sandstone 205 7.2.In Alat Sandstone 206 7.2.2 Ketungau Basin Sequence 210 7.2.2a Kantu Formation 210 7.2.2b Tutoop Sandstone 214 7.2.2c Ketungau Formation 216 7.3 PROVENANCE 218 7.3.1 Melawi Basin 218 7,3,2 Ketungau Basin 225 7.4 DIAGENETIC IMPLICATIONS 226 7.5 TECTONIC SETTING 229 CHAPTER EIGHT - CONCLUSIONS 237 REFERENCES 2 43 VOLUME TWO FIGURES FOR CHAPTER ONE FIGURES FOR CHAPTER TWO FIGURES FOR CHAPTER THREE FIGURES FOR CHAPTER FOUR FIGURES FOR CHAPTER FIVE FIGURES FOR CHAPTER SIX FIGURES FOR CHAPTER SEVEN TABLES FOR CHAPTER 2 TABLES FOR CHAPTER 3 TABLES FOR CHAPTER 4 TABLES FOR CHAPTER 5 TABLES FOR CHAPTER 6 APPENDICES 1-9 STRATIGRAPHIC COLUMNS (IN MAP POCKET) APPENDIX 10 FOSSIL DESCRIPTIONS APPENDICES 11-12 PETROGRAPHIC DATA APPENDICES 13-21 CLUSTER ANALYSIS DATA APPENDIX 22 CROSS-BED ANALYSIS DATA The contents of this thesis are the results of original research and the material included has not been submitted for a higher degree to any other university or similar institutio Rachmat Heryanto Sutjipto ABSTRACT The Melawi and Ketungau Basins are located in West Kalimantan, Indonesia. The Ketungau Basin developed between a Tertiary subduction complex (Lubuk Antu Melange) on the Kalimantan-Sarawak border and the Semitau High to the south. The basin is about 50 km wide, 150 km long and it continues eastward into the Mandai Basin. The Semitau High is a linear structural zone comprising submarine slope deposits, a belt of Cretaceous subduction complex (Boyan Melange) and Permian granitoid and metamorphic rocks. The Melawi Basin sequences were deposited between the Semitau High and the continental basement (Schwaner Zone) to the south. The basin is about 75 km wide and 300 km long. The shallow marine to terrestrial sequences in the Melawi and Ketungau Basins were deposited during the Late Eocene to Oligocene. The Melawi Basin succession comprises four main units separated by periods of uplift and erosion: (1) Ingar Formation - a deep outer shelf marine mudstone; (2) Suwang Group - fluviatile sandstone and lagoonal to marine trough shale; (3) Melawi Group fluviatile to shallow marine clastic deposits; and (4) Kapuas Group - fluviatile sandstone at the top of the succession. The Ketungau Basin consists of a conformable sequence (the Merakai Group) of shallow marine and floodplain deposits, overlain successively by fluviatile sandstone and floodplain to marginal marine mudstone. The alternation between marine and terrestrial sequences, and the presence of three unconformities in the Melawi Basin, indicates tectonic instability during the depositional histories of the basins. On the basis of sandstone petrology, diagenesis and depositional facies the Melawi Group and Alat Sandstone in the Melawi Basin can be correlated, respectively, with the Kantu Formation and Tutoop Sandstone in the Ketungau Basin. Both palaeocurrent and provenance studies indicate derivation of the Melawi and Ketungau Basin sequences from the north, mainly from uplifted recycled orogenic material in the Boyan and Lubok Antu Melanges. A few units in the Melawi Basin contain magmatic arc detritus derived from the Schwaner Mountains to the south. Although both basins contain coal seams, the best quality coal is at the top of the Melawi Basin sequence. Organic maturation and vitrinite abundance indicate that both basins have potential for the generation and entrapment of petroleum. Late Cretaceous subduction in northwestern Kalimantan deformed the Late Cretaceous marine sequence producing the Boyan Melange which incorporated Permian granitic microcontinental fragments. Uplift of the Simitau High (Boyan Melange) along backthrusts during the Paleocene and Early Eocene produced an accretionary prism flanked to the south by the forearc Melawi Basin.